Portion of a substrate for an electronic circuit



FIG. 1 is a front, bottom and left side perspective view of a portion of a substrate for an electronic circuit, showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a rear elevational view thereof.

The uneven spaced broken lines define the bounds of the claimed design and form no part thereof. The even spaced broken line showing of the substrate for an electronic circuit is for illustrative purpose only and forms no part of the claimed design. 

The ornamental design for a portion of a substrate for an electronic circuit, as shown and described. 